Dating device for printers

ABSTRACT

A printer including a printing plate, a dating device having a detachable unit which is detachably connected to the printing plate, and a movable hammer for applying a force to the dating device. The dating device has an axle of polygonal cross-section, type wheels including a rim of elastically deformable material with a polygonal inner-section movably mounted on the axle and connected to the printing plate to be movable in the direction of movement of the hammer, and types on the type wheels. The types on the type wheels opposite those types which are in the printing position are located at a distance from the printing plate.

United States Patent [191 Wirth 1 Sept. 30, 1975 1 1 DATING DEVICE FORPRINTERS [75] inventor: Johannes Wirth, Zurich,

211 Appl. No.: 412,959

OTHER PUBLICATIONS Rogers N, Flexible Print Stick, IBM TechnicalDisclosure Bulletin, Vol. 3, No. 6, Nov. 1960.

Primary liruminer Edgar S. Burr Assistant E.\'uminer-Edward M. CovenAttorney, Agent, or FirmStevens, Davis, Miller & Mosher [57] ABSTRACT Aprinter including a printing plate. a dating device having a detachableunit which is detachably connected to the printing plate. and a movablehammer for applying a force to the dating device. The dating device hasan axle of polygonal cross-section, type wheels including a rim ofelastically deformable material with a polygonal inner-section movablymounted on the axle and connected to the printing plate to be movable inthe direction of movement of the hammer. and types on the type wheels.The types on the type wheels opposite those types which are in theprinting position are located at a distance from the printing plate.

2 Claims, 2 Drawing Figures US. Patent Sept. 30,1975 Sheet 1 of23,908,543

&f. c

US. Patent Sept. 30,1975 Sheet 2 of2 3,908,543

FIG. 2

DATING DEVICE FOR PRINTERS The present invention relates to a datingdevice for a printer with a printing plate and a printing hammer, e.g.,for cash-registers, scales with tag printers for retail or packagingchains, as well as for other apparatuses with similar printing tasks, inwhich, besides an optional text like company or product name, at everyprinting process various data like price and/or weight,

or occasionally changing data like actual date of sale and/or lastallowed date of sale, have to be printed.

In printers incorporated, for example, in commercial cash'registers orpackaging machines, the date of sale or the last allowed date of sale ofa product is generally adjusted by means of type wheels rotating on oneor" several axles fixed in' the apparatus. The date is adjusted on or inthe apparatus itself, either by directly adjusting the type wheels bymeans of a suitable instrument or by turning adjusting disks connectedwith the type wheels for example by means of concentric tubular shafts.

The forces exercized by the printing hammer on the type wheels duringthe printing process have to be absorbed by the axle or the axles of thetype wheels.,ln order to obtain a clear printed image, tolerances andresistance to plastic deformation must be very tight.

If the type wheels are connected with the external adjusting disks bymeans of tubular shafts, the number of type wheels thus being operatedis limited by the strength of the material employed for the tubularshafts. Furthermore, the choice of the position or the location 'of thedate on the printed tag is limited by the other mechanicalcharacteristics of the printer, because generally such a constructionwith tubular shafts is chosen in order to have free access to theadjustment disk. If the construction, because of the mechanical designof the apparatus or the small dimensions of the digits tovbe printed,does not provide tubular shafts, the adjustment of the date has to bemade directly with a suitable instrument. This implies free access tothe type wheels, which fact influences the construction of the printeritself. Furthermore this type of adjustment of the date is bound to acertain minimum size of the characters, which permits good readabilityat normal working distance from the apparatus. The fixed mounting of thedating device in the printer causes the absorption of all the forcesexercized on the types during the printing process by the axles or theshafts of the type wheels, which are connected firmly to the frame.This, together with the small tolerances of the constructive parts ofthe dating device demanded to obtain a clear printed image, requiresconsiderable constructive and economic expense for a dating device.

It is the object of the present invention to create a simply constructeddating device for a printer of the kind mentioned above, which isadjusted externally and independently from the apparatus itself, thus tosimplify not only the construction of the dating device, but also theconstruction of the printer, and besides, to be able to print the dateor the dates on the tag in a convenient position, which is independentfrom the printers construction; a further object of the invention is tobe able to build the constructive parts of the printer with largertolerances than those usually used for printing devices, thus to reducenot only the constructive, but also the economic expense.

According to the invention this is achieved by designing the datingdevice as a detachable unit. This unit is preferably provided with typewheels movably assembled in the direction of motion of the printinghammer. According to a further development of the invention the datingdevice is provided with at least one fixed polygonal axle on whichelastically deformable type wheels with a polygonal inner section areassembled, the characters opposite to those adjustsed for printing beingat a distance from the printing plate and touching it only during theprinting process. Furthermore, it can be provided with two parallelpolygonal axles disposed one upon the other, each one carrying a seriesof type wheels. If the dating device is used on a printer with aprinting block placed on its printing plate, the surface of thecharacters adjusted for printing conveniently projects over the surfaceof the printing block in the direction of the hammer. The type wheelsmay present digits and'other symbols.

An embodiment of the object of the invention is schematicallyrepresented in the accompanying drawing, wherein:

FIG. 1 shows a schematical view of the dating device, with partialsection, and

FIG. 2 shows, in a larger scale, a cross section of the dating deviceassembled on a printer.

The dating device shown in FIG. 1 comprises a frame 5 consisting of twoside plates 1, 2, cross bars 3 and a handle 4. Two two-edged axles 6 aremounted in this frame 5. Their ends are provided with projecting parts 7which engage into corresponding slits of the side plates 1, 2. Four typewheels 8 are assembled on each of these axles 6. In the embodiment shownthe upper series serves for printing the day and the month, the lowerone for printing the year.

Each type wheel 8 is provided with ten characters 9, the digits from Oto 9. Each character 9 is separated from the others by a groove 10. Eachtype wheel 8 has an internal and external decagonal section.

In FIG. 2 the dating device is mounted in the schematically representedprinter. The sole parts of the printer shown are the printing plate 12with fixed printing block 13, the inking ribbon l4 and the printinghammer 15. The dating device is retained by the bent edge 16 of the sideplate 1, which engages in a groove 17 of the printing plate 12, as seenin FIG. 2, and by the cooperation of the two side plates 1 and 2 withthe side walls of an aperture formed in the printing plate 12, theaperture being formed by the two side walls and a back plate 18perpendicular to the two side walls. The whole is constructed in such amanner that the suface of the types of the type wheels 8 being inprinting position project a little over the surface of the printingblock 13. The surface of the opposite types does not touch the backplate 18 of the printing plate 12, but is at a distance from it. As isapparent from FIG. 2, the groove 17 has a sufficient width to allow thebent edge 16 and along with it the entire dating device to slide towardsthe back plate 18 to enable the types on type wheels 8 facing the backplate 18 to contact the plate 18 during the printing process.

The operating principle of the device described is the following: duringthe printing of the date the printing hammer 15 exercises, across thepaper 19 and the inking ribbon 14 placed between the hammer itself andthe dating device, a force on the latter, which deforms elastically thetype wheels 8. The two-edged axles 6 do not absorb considerable forces,because these forces are transmitted to the printing plate 12 over thetypes opposite to those in printing position. The type wheels 8 are incontact with the support only when they have to transmit forces.

In order to adjust the type wheels 8, the dating device is withdrawnfrom the printer and the type wheels 8 are rotated e.g., by means of apin engaging in the groove 10. By this they are also elasticallydeformed, because, as they are gliding over the edges of the axle 6, thedistance of two opposite surfaces of the internal decagon is enlarged.

The device described has numerous advantages. The dating device forms anindependent unit which can be adjusted outside the printer and theninserted in it; if the requirements for the printer change, withsubsequent changes in paper size or format of the adjusted date, anotherdating device may be used, without redesigning the printer. Furthermore,the larger tolerances for the type wheels are advantageous: if theprinting force is' absorbed by the axle or axles of the type wheels,both the type wheels and the axles have to be manufactured with verysmall tolerances, because the types are in contact with the support fromthe beginning. In the device described, the contact with the support isgenerated by the printing process itself, and the type wheels beingelastic, relatively large tolerances for the diameters of the typewheels are admissible. For this reason it is easy to insert the datingdevice.

For the sake of simplicity, the embodiment has been represented as adating device with type wheels which are provided with only ten digits.Practically the type wheels can be provided with more than tencharacters. In some cases this is even necessary. There exist forinstance legal instructions which require, that in the case one numberdate or weight is not printed, a filler symbol, e.g., of an asterisk ora dash, is printed. In other cases, e.g., for perishable goods, besidesthe date, the indication morning or afternoon should be made. For thisthe letters am and pm can be used. Thus, in other embodiments, furthertype wheels with alphanumeric or graphic symbols might be used. Typewheels with the ten digits to 9 and other symbols could also beprovided.

I claim:

1. A printer, comprising: a printing plate having a plurality of sidesforming an aperture extending from a front face of said plate apredetermined distance into said plate to one of said sides whichsubstantially parallel to said front face, and a groove extending alonganother of said sides; a dating device, detachably connected inside saidaperture to said printing plate, including a frame having means which isslidably engaged in said groove to slide backward and forward betweensaid front face and said one side, an axle connected to said framehaving a polygonal cross-section with two opposite first edges, typewheels, of an elastically deformable material, each having a polygonalinner crosssection with a plurality of second edges spaced apart by aplurality of sides, said wheels being rotatably mounted on said axle andin which two of said second edges of said wheels rest on said twoopposite first edges of said axle, the distance between said twoopposite first edges being greater than the distance between any twoopposite sides of said polygonal inner crosssection, wherein when saidwheels are rotated on said axle said inner cross-section is deformed byone of said two opposite first edges; and a movable hammer, locatedopposite said front face of said printing plate, for applying a force tosaid dating device; said dating device further including types on theperiphery of said type wheels, some of said types being in a printingposition facing said hammer and projecting ahead of said front face in adirection towards said hammer, and types on said type wheels oppositesaid types in the printing position being at a predetermined distancefrom said one side of said printing plate forming said aperture, whereinwhen said hammer applies a force to said types in the printing positionsaid frame slides in said groove to enable said types opposite those inthe printing position to contact said one side of said printing plate.

2. A printer according to claim 1 further comprising a printing blockconnected to said front face of said printing plate, and wherein saidtypes in the printing position project ahead of said printing block inthe direction towards said hammer.

1. A printer, comprising: a printing plate having a plurality of sidesforming an aperture extending from a front face of said plate apredetermined distance into said plate to one of said sides whichsubstantially parallel to said front face, and a groove extending alonganother of said sides; a dating device, detachably connected inside saidaperture to said printing plate, including a frame having means which isslidably engaged in said groove to slide backward and forward betweensaid front face and said one side, an axle connected to said framehaving a polygonal cross-section with two opposite first edges, typewheels, of an elastically deformable material, each having a polygonalinner cross-section with a plurality of second edges spaced apart by aplurality of sides, said wheels being rotatably mounted on said axle andin which two of said second edges of said wheels rest on said twoopposite first edges of said axle, the distance between said twoopposite first edges being greater than the distance between any twoopposite sides of said polygonal inner crosssection, wherein when saidwheels are rotated on said axle said inner cross-section is deformed byone of said two opposite first edges; and a movable hammer, locatedopposite said front face of said printing plate, for applying a force tosaid dating device; said dating device further including types on theperiphery of said type wheEls, some of said types being in a printingposition facing said hammer and projecting ahead of said front face in adirection towards said hammer, and types on said type wheels oppositesaid types in the printing position being at a predetermined distancefrom said one side of said printing plate forming said aperture, whereinwhen said hammer applies a force to said types in the printing positionsaid frame slides in said groove to enable said types opposite those inthe printing position to contact said one side of said printing plate.2. A printer according to claim 1 further comprising a printing blockconnected to said front face of said printing plate, and wherein saidtypes in the printing position project ahead of said printing block inthe direction towards said hammer.